electrostatics concept review
Although charges can create a force, they cannot cause another charge to accelerate. True False
False
An object classified as an insulator can never have a charge. True False
False
According to the equation U = 1 CV 2 the energy stored C2 by a capacitor is proportional to its capacitance while according to the equation U = Q2 / 2C the energy stored C by a capacitor is inversely proportional to its capacitance. Is this a contradiction?
No, because potential energy can be proportional or inversely proportional to capacitance, but not at the same time.
Metal sphere A is initially neutral. It is connected by a metal wire to the ground. A positively charged rod is brought near, but not touching. Is A now positive, negative, or neutral? Explain.
A is now negative. Electrons have moved from the ground to the sphere.
Metal sphere A is initially neutral. A positively charged rod is brought near, but not touching. Is A now positive, negative, or neutral? Explain.
A is still neutral. The sphere has become polarized with its left side negative and its right side positive, but the net charge is still zero.
A charge is initially at rest in an electric field. Which of the following correctly describes how the charge will move?
A negative charge will move from lower to higher potential; a positive charge will move from higher to lower potential.
For which of the following devices was a graph of I vs. V a straight line?
A resistor
In which of these circuits will the bulb light?
Closed circuit
Which resistors in the circuit, if any, are in series and which, if any, are in parallel?
R2 and R3 are in parallel; their combination is in series with R1
A parallel-plate capacitor is charged, and then disconnected from the battery that charged it: both plates are now electrically isolated. The capacitor charge, electric field strength, and potential difference are qi , Ei , and (ΔVC )i . Then a dielectric is inserted between the plates. Afterward, the charge, electric field, and potential difference are qf , Ef , and (ΔVC )f . Is E f larger than, smaller than, or the same as Ei ? Explain.
Smaller since the polarization of the dielectric reduces the field strength.
Two ideal light bulbs with resistances 5 Ω and 10 Ω are connected in series or in parallel. Which of the following statements is correct? Hint: The brightness of a bulb is related to the rate at which it changes electrical energy to light, i.e. its power. P = I ΔV = I 2 R = (ΔV )2 / R
The 10 Ω bulb is brighter in series and the 5 Ω bulb is brighter in parallel.
A parallel-plate capacitor has capacitance C. Suppose all three dimensions of the capacitor are doubled—that is, increased by a factor of 2. By what factor does the capacitance increase? Explain
The capacitance is directly proportional to the area of the plates which increases by a factor of 2 × 2 = 4 and inversely proportional to the distance between which increases by a factor of 2. So the net effect is that the capacitance increases by a factor of 4/2 = 2.
Why is the inside of a car a safe place to be during a thunder and lightning storm?
The car is metal. The electrostatic field inside a conductor is zero.
For capacitors in parallel that have different capacitances, which one (if any) has the greatest charge?
The one with the greatest capacitance.
For capacitors in series that have different capacitances, which one (if any) has the greatest potential difference across it?
The one with the smallest capacitance.
Metal spheres A and B in FIGURE Q25.10 are initially neutral and are touching. A positively charged rod is brought near A, but not touching. Is A now positive, negative, or neutral? Use both charge diagrams and words to explain. (+) Rod (+) ---> [(N) Metal Sphere A (N) (N) Metal Sphere B (N)]
The positive rod polarizes the charges in the A+B conductor, attracting negative charges to A and leaving B with excess positive charges. The combined A+B conductor will remain neutral, but A alone has a net negative charge. Note: It is important to notice that the rod is not touching the spheres, therefore charge cannot be transferred.
What is the main advantage of using electric potential instead of electric potential energy?
The potential of a point in space is independent of the sign of the charge placed at that point.
An incandescent light bulb emits light when an electric current through its filament causes it to heat up and glow. Incandescent bulbs are most likely to burn out when you first turn on the bulb. Why?
The resistance of the filament is lowest when the bulb is cold so the current is greatest.
A lightweight metal ball hangs by a thread. When a charged rod is held near, the ball moves toward the rod, touches the rod, then quickly "flies away" from the rod. Explain this behavior.
When the metal ball and the charged rod touch, they exchange charge. Some of the excess charge on the rod will spread over the conducting ball, so that both the rod and the metal ball will have an overall excess charge of the same type. This causes the metal ball and the rod to repel each other.
Metal sphere A has 4 units of negative charge and metal sphere B has 2 units of positive charge. The two spheres are brought into contact. What is the final charge state of each sphere? Explain
When the spheres are in contact electrons move from sphere A to sphere B. By symmetry, the final charge on each sphere must be the same. Since the total initial charge is -4 units +2 units = -2 units, the total final charge must also be -2 units so the charge on each sphere is -1 unit.
Can a conductor be charged? If so, how would you charge a conductor? If not, why not?
Yes a conductor can be charged. A conductor can be charged by touching it with another charged object.
Can an insulator be charged? If so, how would you charge an insulator? If not, why not?
Yes an insulator can be charged. For example, plastic is an insulator and can be charged by rubbing it with wool.
The resistivity of copper is less than the resistivity of aluminum. Can a copper wire and an aluminum wire of the same length have the same resistance?
Yes, if the aluminum wire is thicker.
Metals are the best thermal conductors as well as being the best electrical conductors. Is there any connection between the two?
Yes, since the free electrons that make a metal a good electrical conductor also make it a good thermal conductor.
If you bring your finger near a lightweight, negatively charged hanging ball, the ball swings over toward your finger as shown in FIGURE Q25.11. Use charge diagrams and words to explain this observation. Finger --- (-) Hanging Ball (-)
Your finger becomes polarized. Positive charge is left on the tip of your finger when the negative charges are repelled by the ball. The excess positive charge left on your finger is closer to the negatively charged ball than the negative charge in your finger, resulting in a net attractive force that attracts the ball.
Four point charges lie on the corners of a square of side a. What is the electric potential at the center of the square?
Zero (by symmetry)
If the size of the charge value is tripled for both of two point charges maintained at a constant separation, the mutual force between them will be changed by what factor? a. 9.0 b. 3.0 c. 1/3 d. 1/9
a. 9.0
When a glass rod is rubbed with silk, which of the following statements best describes what happens? a. Electrons are removed from the rod. b. Protons are removed from the silk. c. The silk is charged positively. d. The silk remains neutral.
a. Electrons are removed from the rod.
When charging two objects by rubbing them together: a. Neither may be a conductor. b. They must be made of different material. c. They will sometimes end up with both being positively charged. d. The heat produced by friction is a necessary part of this process.
b. They must be made of different material.
The combination of two separated point charges of opposite sign but equal magnitude is called an electric: a. monopole. b. dipole. c. quadrapole. d. magnapole.
b. dipole.
If body M, with a positive charge, is used to charge body N by induction, what will be the nature of the charge left on the latter? a. must be equal in magnitude to that on M b. must be negative c. must be positive d. must be greater in magnitude than that on M
b. must be negative
An uncharged conductor is supported by an insulating stand. I pass a positively charged rod near the left end of the conductor, but do not touch it. The right end of the conductor will be: a. negative. b. positive. c. neutral. d. attracted.
b. positive.
Two equal charges, each Q, are separated by some distance. What third charge would need to be placed half way between the two charges so that the net force on each charge would be zero? a. -Q b. -Q/2 c. -Q/4 d. -Q/8
c. -Q/4
If the distance between two point charges is tripled, the mutual force between them will be changed by what factor? a. 9.0 b. 3.0 c. 1/3 d. 1/9
d. 1/9
Two point charges are 4 cm apart. They are moved to a new separation of 2 cm. By what factor does the resulting mutual force between them change? a. 1/2 b. 2 c. 1/4 d. 4
d. 4
Reproduce FIGURE Q25.12 on your paper. Then draw a dot (or dots) on the figure to show the position (or positions) where an electron would experience no net force. | | | (+4) | | (-1) | | |
| | | (+4) | | (-1) | | x |
Metal spheres A and B are initially neutral and are touching. A positively charged rod is brought near A, but not touching. Is A now positive, negative, or neutral? Explain.
A is now negative. Electrons have moved from B onto A, leaving A negative and B positive.
The force between two point charges is 1 N. The charges are moved so they are four times as far apart. The force between the charges is now
1/16 N. [F∝1/r2;r→4r;F→(1/42)F]
A -1.0 μC point charge is placed at a point where it experiences an electric force of 0.025 N, down. The electric field at that point is
25,000 N/C, up. (E=F/q)
A force does 2 μJ of work to push charged particle A toward a set of fixed source charges. Charged particle B has twice the charge of A. How much work must the force do to push B through the same displacement? Explain.
4 μJ. Since the force on a charged particle is proportional to its charge, the work done is also proportional to the charge.
What will be the field strength if the distance to the point charge is halved? The quantity of charge is the original amount.
4000 N/C, since the field strength is inversely proportional to the square of the distance
The electric field strength at a point in space near a point charge is 1000 N/C. What will be the field strength if the quantity of charge is halved? Explain
500 N/C, since the field strength is proportional to the charge
Suppose there exists a third type of charge in addition to the two types we've called glass and plastic. Call this third type X charge. What experiment or series of experiments would you use to test whether an object has X charge? State clearly how each possible outcome of the experiments is to be interpreted.
Assume "like repels like" and "opposites attract" still holds. Suspend an object with an excess of the unknown X charge from a string. Approach the object with a plastic-charged rod, and a glass-charged rod. An object with charge X must be attracted to both of these charged rods. However, a neutral rod can also be attract to both charged rods. To determine the object is not neutral, approach a neutral object. If the object has charge X it will be attracted, if it is neutral nothing will happen.
Why can't electric field lines cross?
At the point where they cross the field would have two different directions at the same time, which isn't possible.
Four lightweight balls A, B, C, and D are suspended by threads. Ball A has been touched by a plastic rod that was rubbed with wool. When the balls are brought close together, without touching, the following observations are made: • Balls B, C, and D are attracted to ball A. • Balls B and D have no effect on each other. • Ball B is attracted to ball C. What are the charge states (positive, negative, or neutral) of balls A, B, C, and D? Explain.
Ball A has negative charge since it was touched with a negatively charged rod. Balls B and D are neutral since if either or both were charged there would be a force between them. Ball C is charged since it attracts the neutral ball B. Since it is attracted to ball A, ball C has positive charge.
When a flashlight is operated, what is being used up?
Battery energy
Metal sphere A in FIGURE Q25.9 has 4 units of negative charge and metal sphere B has 2 units of positive charge. The two spheres are brought into contact. What is the final charge state of each sphere? Explain. (-) Metal Sphere A (-) --> Touch <-- (+) Metal Sphere B (+)
Each sphere will both have a final charge state of -1. When they touch, the spheres essentially become on conductor. The overall net charge is (-4) + (+2) = -2. Charge is spread uniformly over the surface of a conductor.
What happens when a battery is charged?
Electrical energy in the charger is changed to chemical energy in the battery.
The electric force on a charged particle in an electric field is F. What will be the force if the particle's charge is tripled and the electric field strength is halved?
F = qE F = (3q)(E/2) = 3/2qE = 3/2 F
The electric field strength at one point near a point charge is 1000 N/C. What is the field strength if (a) the distance from the point charge is doubled, and (b) the distance from the point charge is halved?
For a point charge, E(r) ∝ 1/r^2 a. The electric field strength would decrease. E(2r) ∝ 1/(2r^2) = 1/(4r^2) so, E(2r)/E(r) = [1/(4r^2)] / [1/(r^2] = 1/4 therefore, E(2r) = 1/4 (1000 N/C) = 250 N/C b. The electric field strength would increase. E(r/2) / E(r) = [(1) / (r/2)^2] / [(1/r^2)] = 4 so, E(r/2) = 4 (1000 N/C) = 4000 N/C
What is the direction of the electric field in a parallel plate capacitor?
From the positive plate to the negative plate. From high potential to low potential.
Immediately after a plastic rod is given a net negative charge by rubbing it with fur, the fur...
Has an equal positive charge (since charge is conserved)
The wires in the figure carry the currents shown. How do the magnitudes of the unknown currents compare?
IC>IA>IB
Four lightweight balls A, B, C, and D are suspended by threads. Ball A has been touched by a plastic rod that was rubbed with wool. When the balls are brought close together, without touching, the following observations are made: • Balls B, C, and D are attracted to ball A. • Balls B and D have no effect on each other. • Ball B is attracted to ball C What are the charge states (glass, plastic, or neutral) of balls A, B, C, and D? Explain.
The charge state of ball A is plastic because it was charged by a plastic rod. The charge state of ball B is neutral because it has no affect on D. The charge state of ball C is glass because it is attracted to ball B and ball A. The charge state of ball D is neutral because it has no affect on B. - Neutral is attracted to both glass and plastic.
A parallel plate capacitor is charged by connecting it to a battery. What are the plates charges and overall net charge on the capacitor?
One plate has a charge of +Q. The other plate has a charge of -Q, The net charge on the capacitor is zero.
A comb is given a net electric charge. Which of the following will allow you to determine the sign of the charge?
The comb attracts an object known to have a positive charge and repels an object of a known negative charge
Why is the energy of a nuclear reaction, which involves changes in the nucleus of an atom, much greater than that of a chemical reaction, which involves changes in the electron shells of an atom?
The distance between the protons is much smaller than the distance between the electrons and the nucleus and between the electrons.
The plates of a parallel-plate capacitor are connected to a battery. If the battery voltage is doubled, by what factor does the energy of the capacitor increase?
The energy is proportional to the square of the voltage, so it increases by a factor of 4
The two oppositely charged metal spheres in FIGURE Q25.8 have equal quantities of charge. They are brought into contact with a neutral metal rod. What is the final charge state of each sphere and of the rod? Use both charge diagrams and words to explain. (-) Metal Sphere A (-) --> Metal Rod <-- (+) Metal Sphere B (+)
The final state of each sphere and the rod is neutral. The conducting rod allows excess electrons in the negatively charged sphere to move to the positively charged sphere and exactly neutralizing the charge there. All three conductors are left neutral.
A positively charged rod is held near, but not touching, a neutral metal sphere. Does the sphere experience a net force? If so, in which direction? Explain.
The rod polarizes the sphere. Since the negative side of the sphere is closer to the rod than the positive side of the sphere, the attractive force between the unlike charges is greater than the repulsive force between the like charges, and there is a net force toward the rod.
A parallel-plate capacitor is charged, and then disconnected from the battery that charged it: both plates are now electrically isolated. The capacitor charge, electric field strength, and potential difference are qi , Ei , and (ΔVC )i . Then a dielectric is inserted between the plates. Afterward, the charge, electric field, and potential difference are qf , Ef , and (ΔVC )f . Is qf larger than, smaller than, or the same as qi ? Explain.
The same since the plates are isolated and charge is conserved.
A real battery is connected by ideal wires to a resistor.
The terminal voltage of the battery is less than the emf of the battery and the voltage across the resistor equals the terminal voltage of the battery.
A parallel plate capacitor was charged by a battery and then was disconnected from the battery. What happened to the voltage across the capacitor when the plates were moved farther apart?
The voltage increased
Two oppositely charged metal sphere have equal quantities of charge. They are brought into contact with a neutral metal rod. What is the final charge state of ach sphere and of the rod?
They are all neutral
A negative charge will tend to accelerate in the opposite direction of the electric field. (An electron's acceleration vector points in the opposite direction of the electric field.) True False
True
Three positive particles of equal charge +11.0 μC are located at the corners of an equilateral triangle of side 15.0 cm. What is the direction of the force on the charge on the top corner of the triangle?
Up
Point B is four times as far from the point charge q as point A. What are the correct values for the ratios of the potentials (VB/VA) and field strengths (EB/EA) at the two points?
VB/VA = 1/4; EB/EA = 1/16
Charged plastic and glass rods hang by threads. a. An object repels the plastic rod. Can you predict what it will do to the glass rod? If so, what? If not, why not? b. A different object attracts the plastic rod. Can you predict what it will do to the glass rod? If so, what? If not, why not?
a. Like charges exert repulsive forces on each other. This tells us the object has a plastic charge and will therefore attract the glass charge. b. This object can be glass or neutral and therefore you cannot predict what it will do to the glass rod. If it is a glass object, it will repel the glass rod, but if it is a neutral object it will attract the glass rod.
Three objects are brought close to each other, two at a time. When objects A and B are brought together, they repel. When objects B and C are brought together, they also repel. Which of the following are true? Note: There are multiple correct answers. a. Objects A and C possess charges of the same sign. b. Objects A and C possess charges of opposite sign. c. All three of the objects possess charges of the same sign. d. One of the objects is neutral. e. We would need to perform additional experiments to determine the signs of the charges.
a. Objects A and C possess charges of the same sign. e. We would need to perform additional experiments to determine the signs of the charges.
What is the origin of "static cling"? This a phenomenon that sometimes affects clothing in the dryer. a. The clothes rub against each other. b. Electricity is sent through the metal tumbler to the clothing. c. The removal of the water from the clothes causes them to be more conductive to charge. d. The clothes are not charged, the person touching them is.
a. The clothes rub against each other.
A negatively charged electroscope has separated leaves. a. Suppose you bring a negatively charged rod close to the top of the electroscope, but not touching. How will the leaves respond? Use both charge diagrams and words to explain. b. How will the leaves respond if you bring a positively charged rod close to the top of the electroscope, but not touching? Use both charge diagrams and words to explain.
a. The leaves will separate more. This is because the negatively charged rod will repel the negative charges on top of the electroscope, pushing more negative charge down the leaves. b. The leave will close together. This is because the positively charged rod will attract more negative charges to the top of the electroscope and will depart toward the positively charged rod.
Charges A and B in FIGURE Q25.13 are equal. Each charge exerts a force on the other of magnitude F. Suppose the charge of B is increased by a factor of 4, but everything else is unchanged. In terms of F, (a) what is the magnitude of the force on A, and (b) what is the magnitude of the force on B? <--- F vector --- (+A) === (+B) --- F vector ---> ? (+A) === (+4B) ?
a. The magnitude on the force of A would increase by a factor of +4. F (A) = 4F b. By Newton's Third Law, the force of A on B is equal in magnitude to the force of B on A. Therefore the force on B also increases by a factor of +4. F(A) = F(B) = 4F
Two point charges of unknown magnitude and sign are a distance d apart. The electric field is zero at one point between them, on the line joining them. What can you conclude about the charges? a. The two charges have the same sign. b. The charges have an equal value. c. The two charges have opposite signs. d. This cannot happen with only two charges.
a. The two charges have the same sign.
A charged insulator and an uncharged metal object near one another ______________ . a. attract one another electrically. b. exert no electric force on one another. c. repel one another electrically. d. attract or repel, depending on whether the charge is positive or negative.
a. attract one another electrically.
Which of the following best characterizes electrical insulators? a. charges on the surface don't move b. high tensile strength c. electric charges move freely d. good heat conductors
a. charges on the surface don't move
A metal sphere is initially uncharged. After being touched by a charged rod, the metal sphere is positively charged. The mass of the sphere is now ___________. a. lower. b. higher. c. the same.
a. lower.
A positively charged rod is brought close to a neutral piece of paper, which it attracts. The positively charged rod is removed, the paper is grounded to make it neutral again, and a negatively charged rod is brought close to the piece of paper. The negatively charged rod
attracts the piece of paper.
A repelling force must occur between two charged objects under which conditions? a. Charges are of unlike signs. b. Charges are of like signs. c. Charges are of equal magnitude. d. Charges are of unequal magnitude.
b. Charges are of like signs.
Susan rubs a piece of fur on a hard rubber rod, giving the rod a negative charge. What happens? a. Protons are removed from the rod. b. Electrons are added to the rod. c. The fur is also charged negatively. d. The fur is left neutral.
b. Electrons are added to the rod.
Object A has a charge of +2 C, and object B has a charge of +6µC. Which statement is true about the electric force on the objects? a. FAB = -3FBA b. FAB = -FBA c. 3FAB = -FBA d. FAB = FBA e. 3FAB = FBA
b. FAB = -FBA
I wish to use a positively charged rod to charge a ball by induction. Which statement is correct? a. The charge on the ball will be positive. b. The ball must be a conductor. c. The ball must be an insulator that is connected temporarily to the ground. d. The ball is charged as the area of contact between the two increases.
b. The ball must be a conductor.
Two identical pith balls supported by insulating threads hang side by side and close together, as shown below. One is positively charged; the other is neutral. We can conclude that a. all field lines leaving the positively charged pith ball end on the neutral pith ball. b. some of the field lines leaving the positively charged pith ball end on the neutral pith ball. c. none of the field lines leaving the positively charged pith ball end on the neutral pith ball. d. positive charge is transferred along the field lines until both balls have equal charges. e. positive charge is transferred along the field lines until both balls hang along vertical lines.
b. some of the field lines leaving the positively charged pith ball end on the neutral pith ball.
Charges q, q, and -q are placed on the x-axis at x = 0, x = 2 m, and x = 4 m, respectively. At which of the following points does the electric field have the greatest magnitude? a. x = 1 m b. x = 3 m c. x = 5 m d. The electric field has the same magnitude at all these positions.
b. x = 3 m
Rubber rods charged by rubbing with cat fur repel each other. Glass rods charged by rubbing with silk repel each other. A rubber rod and a glass rod charged respectively as above attract each other. A possible explanation is that a. Any two rubber rods charged this way have opposite charges on them. b. Any two glass rods charged this way have opposite charges on them. c. A rubber rod and a glass rod charged this way have opposite charges on them. d. All rubber rods always have an excess of positive charge on them. e. All glass rods always have an excess of negative charge on them.
c. A rubber rod and a glass rod charged this way have opposite charges on them.
Object A has a charge q on it, object B has a charge q on it, and object C has a charge 2q on it. These charges are arranged, one each, at the vertices of an equilateral triangle. Which charge has the greatest magnitude electric force on it? a. A b. B c. C d. All have equal magnitude forces on them.
c. C
The constant ke, which appears in Coulomb's law formula, is equivalent dimensionally to which of the following? a. N×m/C b. N/C c. N×m^2/C^2 d. N/C^2
c. N×m^2/C^2
How can a charged object attract an uncharged object made of non-conducting material? a. The uncharged object must somehow gain a like charge. b. The uncharged object must somehow gain an unlike charge. c. The charges in the uncharged object can become polarized. d. Attraction of an insulator is not possible.
c. The charges in the uncharged object can become polarized.
Which of the following best characterizes electrical conductors? a. low mass density b. high tensile strength c. electric charges move freely d. poor heat conductors Check
c. electric charges move freely
If body P, with a positive charge, is placed in contact with body Q (initially uncharged), what will be the nature of the charge left on Q? a. must be equal in magnitude to that on P b. must be negative c. must be positive d. must be greater in magnitude than that on P
c. must be positive
The electric field of a point charge has an inverse ________ behavior. a. r^1/2 b. r c. r^2 d. r^3
c. r^2
The number of electric field lines passing through a unit cross sectional area is indicative of a. the field direction b. the charge density c. the field strength d. a charge in motion
c. the field strength
Which is not a force? a. gravity b. electric c. voltage d. friction
c. voltage
Two small objects are suspended from threads. When the objects are moved close together, they attract one another. What of the following could produce this result? a. On object is positively charged and the other is negatively charged. b. One object is positively charged and the other conductor is uncharged. c. One object is negatively charged and the other conductor is uncharged. d. All of the above could result in an attraction.
d. All of the above could result in an attraction.
Two small objects are suspended from threads. When the objects are moved close together, they attract one another. Which of the following could produce this result? a. One object is positively charged and the other is negatively charge. b. One object is positively charged and the other is uncharged. c. One object is negatively charged and the other is uncharged. d. All of the above could result in such attraction.
d. All of the above could result in such attraction.
Two identical balls have the same amount of charge, but the charge on ball A is positive and the charge on ball B is negative. The balls are placed on a smooth, level, frictionless table whose top is an insulator. Which of the following is true? a. Since the force on A is equal but opposite to the force on B, they will not move. b. They will move together with constant acceleration. c. Since the force on both balls is negative, they will move in the negative direction. d. None of the above is correct.
d. None of the above is correct.
Which of the following characteristics are held in common by both gravitational and electrostatic forces when dealing with either point masses or charges? a. inverse square distance law applies b. forces are conservative c. potential energy is a function of distance of separation d. all of the above choices are valid
d. all of the above choices are valid
Enrico says that positive charge is created when you rub a glass rod with silk, and that negative charge is simply the absence of positive charge. Rosetta says that negative charge is created and that positive charge is the absence of positive charge. (She has heard that Ben Franklin should have reversed the signs he associated with the charges.) Which one, if either, is correct? a. Enrico, because there really is only one kind of charge. b. Rosetta, because there really is only one kind of charge. c. Neither: although no charge is present originally, both types of charge are created through friction. d. Both: only one type of charge is created by friction at any one time. e. Neither: both negative and positive charge are present simultaneously in all solid materials on Earth and the process described involves a transfer of charge, not the creation of charge.
e. Neither: both negative and positive charge are present simultaneously in all solid materials on Earth and the process described involves a transfer of charge, not the creation of charge.
When a positive charge q is placed in the field created by two other charges Q1 and Q2, each a distance r away from q, the acceleration of q is a. in the direction of the charge Q1 or Q2 of smaller magnitude. b. in the direction of the charge Q1 or Q2 of greater magnitude. c. in the direction of the negative charge if Q1 and Q2 are of opposite sign. d. in the direction of the positive charge if Q1 and Q2 are of opposite sign. e. in a direction determined by the vector sum of the electric fields of Q1 and Q2.
e. in a direction determined by the vector sum of the electric fields of Q1 and Q2.
In an RC circuit, current flows from the battery until the capacitor is completely charged. The total energy stored by the capacitor equals
the total energy supplied by the battery minus the energy dissipated by the resistor.
